The present invention relates to a method of soldering the terminals of an electronic component to conductive paths of a board by applying a soldering strip of solder material which bridges over a plurality of terminals followed by feeding heat in order to melt the solder strip. The invention also concerns a foil for the carrying out of this method.
Electronic components have up to now generally been soldered to the conductive paths of a board by means of a so-called solder wave. This necessarily leads to different layer thicknesses of the conductive paths which extend in longitudinal and transverse direction.
Furthermore, in the case of large layer thicknesses there are strong stresses between the conductive path coated with solder and the support which has the conductive path, which may lead to a loosening of the conductive paths.
In the case of liquid crystal displays it is also known to apply over the conductive paths a foil which bears strips of solder on the side facing away from the conductive paths, these strips bridging over the conductive paths which are to be contacted by electric terminals of electronic components. Wherever an electric terminal is to be soldered to a conductive path, a small cutout in the form of a window is provided in the foil. After the placing-on of the foil, the electronic components are placed on the foil and heat is then fed by means of a ram which presses against the terminals. This method of soldering has the disadvantage that the individual cutouts must agree very precisely in dimensions with the position of the conductive paths. In particular, if a number of components are to be soldered on a support one after the other and if foil with strips of solder from a roll is to be used for this, such strong deviations between the cutouts and the conductive paths result due to the summation of tolerances that proper soldering is no longer assured.